Unity 4 - 3D Textures (Volumes)

Here's a small example C# script:

Code (csharp):

1.  
2.  
3. using UnityEngine;
4.  
5. public class Create3DTex : MonoBehaviour {
6.    
7.     public Texture3D tex;
8.     public int size = 16;
9.  
10.     void Start ()
11.     {
12.         tex = new Texture3D (size, size, size, TextureFormat.ARGB32, true);
13.         var cols = new Color[size*size*size];
14.         float mul = 1.0f / (size-1);
15.         int idx = 0;
16.         Color c = Color.white;
17.         for (int z = 0; z < size; ++z)
18.         {
19.             for (int y = 0; y < size; ++y)
20.             {
21.                 for (int x = 0; x < size; ++x, ++idx)
22.                 {
23.                     c.r = ((x1)!=0) ? x*mul : 1-x*mul;
24.                     c.g = ((y1)!=0) ? y*mul : 1-y*mul;
25.                     c.b = ((z1)!=0) ? z*mul : 1-z*mul;
26.                     cols[idx] = c;
27.                 }
28.             }
29.         }
30.         tex.SetPixels (cols);
31.         tex.Apply ();
32.         renderer.material.SetTexture ("_Volume", tex);
33.     }  
34. }
35.  

...and a simple shader that uses it (uses object space positions as 3D texture coordinates):

Code (csharp):

1.  
2. Shader "DX11/Sample 3D Texture" {
3. Properties {
4.     _Volume ("Texture", 3D) = "" {}
5. }
6. SubShader {
7. Pass {
8.  
9. CGPROGRAM
10. #pragma vertex vert
11. #pragma fragment frag
12. #pragma exclude_renderers flash gles
13.  
14. #include "UnityCG.cginc"
15.  
16. struct vs_input {
17.     float4 vertex : POSITION;
18. };
19.  
20. struct ps_input {
21.     float4 pos : SV_POSITION;
22.     float3 uv : TEXCOORD0;
23. };
24.  
25.  
26. ps_input vert (vs_input v)
27. {
28.     ps_input o;
29.     o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
30.     o.uv = v.vertex.xyz*0.5+0.5;
31.     return o;
32. }
33.  
34. sampler3D _Volume;
35.  
36. float4 frag (ps_input i) : COLOR
37. {
38.     return tex3D (_Volume, i.uv);
39. }
40.  
41. ENDCG
42.  
43. }
44. }
45.  
46. Fallback "VertexLit"
47. }
48.  

 

Yes, in 4.0. It's not DX11 specific however, 3D textures work on D3D9, D3D11, OpenGL, Xbox 360 etc. They definitely do not work on Flash or mobile right now, since those platforms currently just can't support them.

 

Into slices: not in 4.0 - but I guess I could look into adding that. But on DX11 you can arbitrarily write into a 3D render texture using "random write" (UAV in DX11 lingo); e.g. if you're computing some fluid simulation from a compute shader and writing the results into a 3D texture.

Good question, I haven't tried that.

I think if you setup multiple render targets (possible since Unity 3.5) and just have a geometry shader that outputs to one of them, then all should just work (tm). We don't have any way of setting up multiple viewports in Unity right now however.

 

Yes.